add the caller to your contacts. Then locate the person in your contacts. Once you do that you can click on the icon for information. At the bottom of that screen will be an option to block the caller. This will block calls and texts.

I have a specific contact called "do not answer." all the numbers I don't want to bother me gets added to that same contact name. The "contact" is already blocked. I just keep saving numbers to it like from telemarketers, etc.